1. Field of the Invention
This invention relates generally to ventilator units and more particularly to metal ventilator units installed within a window frame.
2. Description of the Prior Art
The use of ventilator units constructed predominately of aluminum or other metals is common. The metal construction contributes to the unit's strength, durability, and resistance to weather. Furthermore, such shaping techiques as the extrusion of aluminum allow for the ready forming of complex channels, ridges, and other structures adapted to hold the glass of the window with which the ventilator is associated or to engage other surrounding structures.
Unfortunately, a heat transfer problem may be associated with the use of conventional metal ventilators. Heat from the warmer side of the ventilator flows through the metal to the other, cooler side, so that in winter, for example, a significant heat loss to the outside air may occur even though the ventilator itself is closed. The result is discomfort for occupants of the building, undesirable waste of energy, and higher fuel bills. In extreme cases, frost may form on the interior metal surfaces. The water formed when frost melts can damage paint, draperies, carpeting, or other materials with which it comes in contact. In the summer, exterior heat is transferred to interior, air conditioned areas in the same manner. Again, an undesirable waste of energy results.